Ascertaining configuration of a virtual adapter in a computing environment

ABSTRACT

A control component of a computing environment activates a virtual adapter hosted on a physical adapter of a host system of the computing environment. The virtual adapter is for use by a guest of the host system in performing data input and output. The activating activates the virtual adapter absent involvement of the guest. Based on activating the virtual adapter, the control component obtains configuration information of the activated virtual adapter from the physical adapter, the configuration information generated based on the activating. The control component ascertains a configuration of the activated virtual adapter based on the obtained configuration information.

BACKGROUND

In a computing environment in which multiple guests share a commonphysical adapter of a host system, each guest may be assigned arespective virtual adapter for use in performing data input and output.Multiple guest operating systems, for instance, may share a physicalhost bus adapter (HBA), such as a physical fibre channel adapter, toprovide connectivity to a network. A physical fibre channel adapter mayinclude multiple virtual host bus adapters (HBAs), each dedicated foruse by a respective guest. Typically, a guest will load, i.e. by a bootsequence or initial program load (IPL), into an operating system thatwill issue commands to bring up, or activate, a virtual adapter assignedto service the guest data input/output (I/O) requests. In channel I/Otechnologies, these commands are provided as a channel program ofspecialized instructions known as channel command words, or “CCWs”, toactivate a virtual HBA on the shared physical channel adapter. Theactivated virtual HBA will be assigned unique identifiers and otherconfiguration information. For instance, the activated virtual HBA willreach out to the network and request an identifier that uniquelyidentifies the virtual device within the network.

In large-scale fibre channel networks, endpoints that connect devices toa fabric are known as node ports (“N_ports”). In a storage area network(SAN), as one example, N_ports include ports of the storage devices inaddition to the ports of the physical HBAs that access them. These areexamples of physical N_ports, though N_ports may also be virtual.Virtual HBAs and other types of virtual adapters that communicate withnetwork devices are termed virtual N_ports.

Both virtual and physical N_ports are assigned a fibre channelidentifier (“N_port ID” or “fibre channel id”) to uniquely identify theN_port within the local fibre channel network. N_ports—both physical andvirtual—login to the network and request the fibre channel id from thefabric. Further, a global unique identifier called a world wide portname (WWPN) is assigned by a system, such as a central electronicscomplex, of which the N_port is a part. Any host bus adapter, physicalor virtual, within a fibre channel environment has an associated WWPN touniquely identify that component within the environment. Additionalconfiguration information may be assigned to host bus adapters withinthe environment, which may include hundreds of such host bus adaptersand therefore an equally large number of unique HBA configurations.

SUMMARY

Determining and managing a large number of unique configurations foradapters of a computing environment can be challenging, especially givenconventional practices in which the configuration for an adapter isdetermined after the entity which is to use the adapter (for instance aguest system) is loaded and issues requests to obtain such information.Validation of that configuration information and of access controlsbeing enforced by the network to control access by the adapters to thosenetwork components is impractical under such circumstances.

Shortcomings of the prior art are overcome and additional advantages areprovided through the provision of a computer program product including acomputer readable storage medium readable by a processing circuit andstoring instructions for execution by the processing circuit forperforming a method which includes activating, by a control component ofa computing environment, a virtual adapter hosted on a physical adapterof a host system of the computing environment, the virtual adapter foruse by a guest of the host system in performing data input and output,wherein the control component is separate from the host system, and theactivating comprises the control component providing a request to thephysical adapter that the virtual adapter be activated; based onactivating the virtual adapter, obtaining, by the control component,configuration information of the activated virtual adapter from thephysical adapter, the configuration information generated based on theactivating; and ascertaining, by the control component, a configurationof the activated virtual adapter based on the obtained configurationinformation, wherein the activating activates the virtual adapter absentinvolvement of the guest.

Further, a system is provided. The system includes a memory and aprocessor in communications with the memory, wherein the computer systemis configured to perform a method, the method including: activating, bya control component of a computing environment, a virtual adapter hostedon a physical adapter of a host system of the computing environment, thevirtual adapter for use by a guest of the host system in performing datainput and output, wherein the control component is separate from thehost system, and the activating comprises the control componentproviding a request to the physical adapter that the virtual adapter beactivated; based on activating the virtual adapter, obtaining, by thecontrol component, configuration information of the activated virtualadapter from the physical adapter, the configuration informationgenerated based on the activating; and ascertaining, by the controlcomponent, a configuration of the activated virtual adapter based on theobtained configuration information, wherein the activating activates thevirtual adapter absent involvement of the guest.

Yet further, a method is provided which includes activating, by acontrol component of a computing environment, a virtual adapter hostedon a physical adapter of a host system of the computing environment, thevirtual adapter for use by a guest of the host system in performing datainput and output, wherein the control component is separate from thehost system, and the activating comprises the control componentproviding a request to the physical adapter that the virtual adapter beactivated; based on activating the virtual adapter, obtaining, by thecontrol component, configuration information of the activated virtualadapter from the physical adapter, the configuration informationgenerated based on the activating; and ascertaining, by the controlcomponent, a configuration of the activated virtual adapter based on theobtained configuration information, wherein the activating activates thevirtual adapter absent involvement of the guest.

Additional features and advantages are realized through the concepts ofaspects of the present invention. Other embodiments and aspects of theinvention are described in detail herein and are considered a part ofthe claimed invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

One or more aspects of the present invention are particularly pointedout and distinctly claimed as examples in the claims at the conclusionof the specification. The foregoing and other objects, features, andadvantages of the invention are apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 depicts one example of a computing environment to incorporate anduse one or more aspects described herein;

FIG. 2 depicts another example of a computing environment to incorporateand use one or more aspects described herein;

FIG. 3A depicts yet another example of a computing environment toincorporate and use one or more aspects described herein;

FIG. 3B depicts further details of the memory of FIG. 3A;

FIG. 4 depicts further details of a computing environment in whichvirtual adapters are activated by a control element, in accordance withone or more aspects described herein;

FIG. 5 depicts an example in which a control element initiates sendingof requests by a virtual adapter into a storage area network, inaccordance with aspects described herein;

FIG. 6 depicts an example process for ascertaining configuration of avirtual adapter, in accordance with aspects described herein;

FIG. 7 depicts an example process for determining access controls beingenforced to control access by an activated virtual adapter to componentsof a network, in accordance with aspects described herein;

FIG. 8 depicts one embodiment of a computer program product;

FIG. 9 depicts one embodiment of a host computer system;

FIG. 10 depicts a further example of a computer system;

FIG. 11 depicts another example of a computer system comprising acomputer network;

FIG. 12 depicts one embodiment of various elements of a computer system;

FIG. 13A depicts one embodiment of the execution unit of the computersystem of FIG. 12;

FIG. 13B depicts one embodiment of the branch unit of the computersystem of FIG. 12;

FIG. 13C depicts one embodiment of the load/store unit of the computersystem of FIG. 12;

FIG. 14 depicts one embodiment of an emulated host computer system;

FIG. 15 depicts one embodiment of a cloud computing node;

FIG. 16 depicts on embodiment of a cloud computing environment; and

FIG. 17 depicts one example of abstraction model layers.

DETAILED DESCRIPTION

In accordance with aspects described herein, capabilities are providedto activate a virtual adapter, obtain configuration information of theactivated virtual adapter, and ascertain based on the configurationinformation a configuration of the virtual adapter by a controlcomponent. This may be performed absent involvement of a guest system orother entity that the virtual adapter services for data I/O processing,and optionally as that entity remains inactive (stopped or even beforeit is present in host memory). Further capabilities are provided toinitiate sending of requests from the activated virtual adapter into thenetwork to determine access controls being enforced to control access bythe virtual adapter to network components. Requests may be issued toremote endpoints of the network, such as storage devices, andconfiguration aspects of the network and the virtual adapter determinedbased thereon. Based on discovering configuration(s) that are improper,they may adjusted, if desired. This may be performed for many virtualadapters of the computing environment absent involvement of guests thatuse, or will use, the virtual adapters, and optionally absent the needto activate (load or boot) the guest systems that will use the virtualadapters.

Computing environments of different architectures may incorporate anduse one or more aspects provided herein. For instance, environmentsbased on the PowerPC architecture, also referred to as Power ISA,offered by International Business Machines Corporation (IBM®) anddescribed in the Power ISA′ Version 2.06 Revision B specification, Jul.23, 2010, hereby incorporated by reference herein in its entirety, mayinclude one or more aspects, as well as computing environments of otherarchitectures, such as the z/Architecture, offered by InternationalBusiness Machines Corporation, and described inz/Architecture-Principles of Operation, Publication No. SA22-7932-09,10th Edition, September 2012, which is hereby incorporated by referenceherein in its entirety.

Z/ARCHITECTURE, IBM, Z/OS and Z/VM (referenced herein) are registeredtrademarks of International Business Machines Corporation, Armonk, N.Y.Other names used herein may be registered trademarks, trademarks orproduct names of International Business Machines Corporation or othercompanies.

One example of a computing environment to incorporate and use one ormore aspects described herein is provided with reference to FIG. 1. Inone example, a computing environment 100 includes a processor (centralprocessing unit—CPU) 102. Processor 102 is communicatively coupled to amemory portion 108 having, for instance, a cache (not pictured), and toan input/output (I/O) portion 112. I/O portion 112 is communicativelycoupled to external I/O devices 114 that may include, for example, datainput devices, sensors and/or output devices, such as displays.

A further embodiment of a computing environment to incorporate and useone or more aspects described herein is depicted in FIG. 2. Referring toFIG. 2, in one example, a computing environment 200 includes a centralprocessor complex (CPC) 202 (also referred to as a Central ElectronicComplex—“CEC)” coupled to one or more input/output (I/O) devices 204through I/O subsystem 212. Central processor complex 202 includesprocessor memory 208 (a.k.a., main memory, main storage, centralstorage) coupled to one or more central processors (a.k.a., centralprocessing units (CPUs)) 210 and I/O subsystem 212, each of which isfurther described below.

Processor memory 208 includes one or more virtual machines 214 (for oneexample of the PowerPC architecture) or one or more logical partitions214 (for one example of the z/Architecture), and processor firmware 216,which includes a hypervisor 218 and other processor firmware 220. Asused herein, firmware includes, e.g., the microcode and/or millicode ofthe processor. It includes, for instance, the hardware-levelinstructions and/or data structures used in implementation of higherlevel machine code. In one embodiment, it includes, for instance,proprietary code that is typically delivered as microcode that includestrusted software or microcode specific to the underlying hardware andcontrols operating system access to the system hardware.

Each virtual machine or logical partition 214 functions as a separatesystem and has one or more applications 222, and optionally, a residentoperating system 224 therein, which may differ for each virtual machineor logical partition. In one embodiment, the operating system is thez/VM operating system, the z/OS operating system, the z/Linux operatingsystem, or the TPF operating system, offered by International BusinessMachines Corporation, Armonk, N.Y. The virtual machines are managed byhypervisor 218, such as PowerVM, offered by International BusinessMachines Corporation, Armonk, N.Y.; and the logical partitions aremanaged by hypervisor 218, such as the Processor Resource/System Manager(PR/SM), offered by International Business Machines Corporation, Armonk,N.Y.

The virtual machines are hosted on a host system, i.e. CEC 202, andtherefore could be considered guests of that host system. As notedabove, each virtual machine may load a guest operating system. In someembodiments, a virtual machine may load a hypervisor or guest operatingsystem that itself hosts one or more guests (one or more other guestoperating systems, for instance). In this manner, a “guest” may refergenerally to a virtual machine or guest operating system that is runningon (“hosted by”) a host system. Multiple levels of guests may exist, allsupported by a lowest level host system (such as CEC 202). Additionally,in some cases, an operating system may itself be, or implement, avirtual machine. Therefore, in some scenarios, a virtual machine may beconsidered a guest operating system, and vice versa. In any case, theterm “guest” as used herein is used broadly to encompass any of theabove possibilities.

Central processors 210 are physical processor resources assignable tothe virtual machines or allocated to the logical partitions. Forinstance, each virtual machine or logical partition 214 includes one ormore logical processors, each of which represents all or a share of aphysical processor 210 that may be dynamically allocated to the virtualmachine or partition. A central processor may include various componentsnot depicted herein, such as a memory management unit, translationlookaside buffer, registers, and caches.

Input/output subsystem 212 directs the flow of information betweeninput/output devices 204 and main memory 208 (in some cases via one ormore I/O control units, not pictured). I/O subsystem 212 is coupled tothe central processing complex in that it can be a part of the centralprocessing complex or separate therefrom. The I/O subsystem relieves thecentral processors of the task of communicating directly with theinput/output devices and permits data processing to proceed concurrentlywith input/output processing. To provide communications, the I/Osubsystem employs I/O communications adapters. There are various typesof communications adapters including, for instance, channels, I/Oadapters, host bus adapters, PCI cards, Ethernet cards, Small ComputerStorage Interface (SCSI) cards, etc. Further, the I/O subsystem uses oneor more input/output paths as communication links in managing the flowof information to or from input/output devices 204.

Another embodiment of a computing environment to incorporate and use oneor more aspects described herein is provided with reference to FIG. 3A.In this example, a computing environment 300 includes, for instance, anative central processing unit (CPU) 302, a memory 304, and one or moreinput/output devices and/or interfaces 306 coupled to one another via,for example, one or more buses 308 and/or other connections. Asexamples, computing environment 300 may include a PowerPC processor, ora pSeries server offered by International Business Machines Corporation,Armonk, N.Y.; an HP Superdome with Intel Itanium II processors offeredby Hewlett Packard Co., Palo Alto, Calif.; and/or other machines basedon architectures offered by International Business Machines Corporation,Hewlett Packard, Intel, Oracle, or others.

Native central processing unit 302 includes one or more native registers310, such as one or more general purpose registers and/or one or morespecial purpose registers used during processing within the environment.These registers include information that represents the state of theenvironment at any particular point in time.

Moreover, native central processing unit 302 executes instructions andcode that are stored in memory 304. In one particular example, thecentral processing unit executes emulator code 312 stored in memory 304.This code enables the computing environment configured in onearchitecture to emulate another architecture. For instance, emulatorcode 312 allows machines based on architectures other than thez/Architecture, such as PowerPC processors, pSeries servers, HPSuperdome servers or others, to emulate the z/Architecture and toexecute software and instructions developed based on the z/Architecture.

Further details relating to emulator code 312 are described withreference to FIG. 3B. Guest instructions 350 stored in memory 304comprise software instructions (e.g., correlating to machineinstructions) that were developed to be executed in an architectureother than that of native CPU 302. For example, guest instructions 350may have been designed to execute on a z/Architecture processor 102, butinstead, are being emulated on native CPU 302, which may be, forexample, an Intel Itanium II processor. In one example, emulator code312 includes an instruction fetching routine 352 to obtain one or moreguest instructions 350 from memory 304, and to optionally provide localbuffering for the instructions obtained. It also includes an instructiontranslation routine 354 to determine the type of guest instruction thathas been obtained and to translate the guest instruction into one ormore corresponding native instructions 356. This translation includes,for instance, identifying the function to be performed by the guestinstruction and choosing the native instruction(s) to perform thatfunction.

Further, emulator code 312 includes an emulation control routine 360 tocause the native instructions to be executed. Emulation control routine360 may cause native CPU 302 to execute a routine of native instructionsthat emulate one or more previously obtained guest instructions and, atthe conclusion of such execution, return control to the instructionfetch routine to emulate the obtaining of the next guest instruction ora group of guest instructions. Execution of the native instructions 356may include loading data into a register from memory 304; storing databack to memory from a register; or performing some type of arithmetic orlogic operation, as determined by the translation routine.

Each routine is, for instance, implemented in software, which is storedin memory and executed by native central processing unit 302. In otherexamples, one or more of the routines or operations are implemented infirmware, hardware, software or some combination thereof. The registersof the emulated processor may be emulated using registers 310 of thenative CPU or by using locations in memory 304. In embodiments, guestinstructions 350, native instructions 356 and emulator code 312 mayreside in the same memory or may be disbursed among different memorydevices.

The computing environments described above are only examples ofcomputing environments that can be used. Other environments, includingbut not limited to, other non-partitioned environments, otherpartitioned environments, and/or other emulated environments, may beused; embodiments are not limited to any one environment.

Traditionally, configurations of virtual adapters, such as virtual hostbus adapters (HBAs), hosted by physical adapters are validated onlyafter booting the individual guest systems (such as guest operatingsystems or virtual machines) that are to use those virtual HBAs. Severalexamples provided herein are described with reference to the FibreChannel data transport protocol. Adapters within the fibre channelcontext are called host bus adapters, with a physical HBA being aphysical fibre channel adapter, and a virtual HBA being a virtual fibrechannel adapter (used interchangeably herein with “virtual HBA”).Channel adapters are used in communicating data in accordance with thefibre channel protocol. Fibre channel adapters are termed “N_ports” inthe fibre channel context. Presently, configuration information, such asthe world wide port names (WWPNs), of these adapters is not known to auser or administrator until the guests that are to use these adaptersare ‘brought online’, i.e. booted or loaded. For virtual adapters usedin a virtual machine environment, for instance, configurationinformation of a virtual adapter associated with a particular guest(e.g. virtual machine or guest operating system) is not known until theguest undergoes an initial program load (IPL) and subsequently isbrought online. This process is usually transparent to users of theguest systems and is not executed until a guest system is booted. Afterthe guest is brought online and the device driver (guest driver for thevirtual adapter) is loaded, a request may be made for the virtual HBA tologin to the network on behalf of that virtual N_port. A WWPN may begenerated within the system of which the adapter is a part (such as aCEC) and used as part of a fabric login process. This is typically theearliest point at which the host (for instance the CEC or a hostingvirtual machine thereof) will be able to acquire certain configurationinformation of the virtual adapter, such as the WWPN or a fibre channelidentifier (id) for that virtual adapter.

As noted above, some computing environments may have hundreds of guestsusing hundreds of corresponding virtual adapters, each assigned its ownunique WWPN, fibre channel id, and other configuration information. Inlight of this, it becomes a tedious, time-consuming, and difficult taskfor an administrator who desires to obtain this configurationinformation and determine configurations of the adapters to load eachguest and then gather this information by requesting each guest toprovide the information to the administrator.

Nonetheless, administrators sometimes desire to obtain configurationinformation of the virtual adapters of a system. This information may beuseful in the configuration of network components, such as in theconfiguration of zoning in a storage area network (SAN) and logical unitnumber (LUN) masking in a storage array. Zoning is used to control whichdevices are accessible to given WWPNs, while LUN masking is used topermit/restrict access (by WWPN) to particular ranges of LUNs within agiven accessible device, thereby serving as a protection mechanism toprevent guests from accessing data of other guests. In this manner,configuration information including the WWPNs may be used by SAN andstorage array administrators to set storage access controls. While it isdesirable to collect this type of configuration information foradministrator use, it is inefficient and burdensome to require that eachguest be loaded in order to gather this information.

When guests are inactive (stopped and not executing, for instance priorto being IPLd for an execution session, or prior to being loaded intoCEC memory, as examples), the virtual adapters (virtual HBAs) exist butare inactive. That is, they are setup insofar as they may be activatedfor a particular guest, but are not yet configured with, e.g., anassigned fibre channel id or WWPN. The virtual adapter may becomeactivated when, for instance, the guest to which the virtual adapter isdedicated starts up and initiates this activation. The informationnecessary for the virtual HBA to become a fully configured virtualadapter exists while the guest is inactive, but the configuration is notconventionally constructed until the guest boots and activates thevirtual adapter.

According to aspects described herein, a separate control componentactivates the virtual adapter, thereby invoking construction of theconfiguration information of the virtual adapter, and does so withoutguest involvement. The configuration information is obtained by thecontrol component absent a need for the guest to be brought online andthe virtual adapter activated by that guest. The configurationinformation may be obtained by the control component and theconfiguration of the virtual adapter may be ascertained therefrom. Theconfiguration mirrors what the configuration will be when the guest isbrought online to use the virtual adapter to perform data input andoutput operations. Thus, the ascertained configuration of the virtualadapter may identify the WWPN, which is the WWPN that will be assignedto the virtual adapter when the guest associated with that adapter iseventually loaded and activates the virtual adapter for use inperforming data input and output.

The configuration information and configuration(s) ascertained therefrommay be used for administrative purposes, for instance in determiningwhether the virtual adapter and/or components to be accessed by thatvirtual adapter are appropriately configured. Additionally, thisactivating, obtaining of configuration information, and ascertaining ofconfiguration may be repeated for many virtual adapters, such as eachavailable virtual HBA on a particular physical channel.

Aspects described herein enable obtaining of configuration informationfor a virtual adapter and ascertaining of the configuration of thatvirtual adapter which may be performed absent any involvement of theguest to which the virtual adapter is, or will become, dedicated. Thismay also be performed absent any communication between the controlcomponent and that guest, and absent any need to load that guest. Theconfiguration or ascertained configurations can be exported, analyzed,tested, debugged, or used in any other manner desired.

Thus, a control component can activate the virtual adapters, obtain theconfiguration information thereof, and ascertains configurations of thevirtual adapters. Cooperating program code (such as firmware) may beprovided within the CEC and/or components thereof, such as the physicalchannel adapter. The provided code may be an extension to existingfirmware of the physical adapter. In some embodiments, the provided codesupports receipt of service requests from the control component. Servicerequests could be commands, for instance control words. The providedcode and control component may communicate directly through the hostsystem absent any interaction with the guest, in order to exchange data,receive the service requests, drive the appropriate functions of thephysical adapter or virtual adapter being activated, obtainconfiguration information, and provide the information to the controlcomponent.

Referring now to FIG. 4, further details are provided of a computingenvironment in which virtual adapters are activated by a control elementin accordance with one or more aspects described herein. System 202 is,for instance, a CEC (FIG. 2) or other physical server, and includescomponents depicted and described with reference to FIGS. 1-3B, some ofwhich have been omitted from depiction in FIG. 4 for convenience.

System 202 of FIG. 4 is a host system hosting a plurality of virtualoperating systems (OSs) 224. In FIG. 4, the virtual OSs 224 are shown asbeing inactive—that is, not running or executing. In this inactivestate, they may reside in memory (storage) but be in stopped or unloadedstate. In one example, they are inactive until they are IPLd and broughtonline. After a session of execution, they may be rendered inactive bypausing or by shutting them down, for instance.

System 202 includes a plurality of guests 224. In the example of FIG. 4,guests 224 are guest virtual OSs. System 202 may include one or morevirtual machines (not pictured) with each different virtual machinehosting one or more virtual OSs 224. As described above, there may bemultiple levels of guests executing within system 202. For example,system 202 may execute one or more guest virtual machines or operatingsystems, with each guest virtual machine or operating system itselfexecuting several guest virtual machines or guest operating systems.

System 202 includes an I/O subsystem 212 having a physical HBA 226. Thephysical HBA hosts multiple virtual HBAs 228 for use by virtual OSs 224.System 202 is in communication with storage area network components 230across one or more communication links 229. Storage area networkcomponents 230 can include storage device(s) to which system 202 isattached and to which virtual HBAs 228 are given access. Thecommunication link(s) may include an intervening network fabric havingone or more network switches, as examples. Many other topologies arepossible, including a point-to-point topology in which system 202 isdirectly connected to a storage device absent any intervening networkfabric or switches.

Conventionally, a virtual OS or other guest would start (load, boot,activate, etc.) and, as part of its execution, activate a virtual HBAassigned to the guest, the virtual HBA for use in performing data inputand output for the guest. Activation by the guest includes causingfunctions of the physical adapter and/or network components to beinvoked to assign the virtual HBA a fibre channel id and WWPN, which maythen be returned to the guest activating the adapter. For instance, theWWPN for the virtual HBA may be obtained by the physical HBA fromfacilities inside the CEC. The fibre channel id (as well as otherinformation) may be obtained from the network. An administrator may thenquery the guest (or an entity that has access to guest state) to obtainthat configuration information and determine therefrom a configurationof the virtual HBA, such as a WWPN assigned thereto.

In accordance with aspects described herein, and as depicted in FIG. 4,a control component (control element 232) is provided. Control element232 is, in this example, a physical component separate from the physicalserver, though in other examples the control component may be part ofphysical server 202. The control element may be incorporated into anexisting separate component for managing a CEC. These are commonlyreferred to as management control elements, service elements, or systemcontrol elements, as examples. In some embodiments, the control elementis provided as part of a Hardware Management Console. The controlelement may be a separate physical system having its own set ofprocessor(s), memory, and the like from that of the CEC that it manages.

Control element 232 is in communication with system 202, for instancethe I/O subsystem or other components thereof, across one or morecommunication paths. The control element can make use of supportfacilities provided within the I/O subsystem, as an example. The supportfacilities may be existing support facilities that facilitate managementof the CEC by a control component. Example support facilities mayinclude flexible service processors (FSPs). FSPs may be, in someexamples, auxiliary processors implemented as firmware and scatteredthroughout a host system (CEC 202, as an example). The control element232 may communicate with a support facility, and vice versa. In someexamples, control element 232 communicates directly with one or moreFSPs (not pictured) of I/O subsystem 212 or other components of system202.

I/O subsystem 212 and/or physical HBA 226 thereof is configured toreceive requests to perform functions including activation andconfiguration of virtual adapters 228. Example requests that may behandled by a physical HBA 226 are commands that are issued by a guest.In accordance with aspects described herein, control element 232 issuesrequests to I/O subsystem 212, or more specifically to physical HBA 226thereof. These requests from the control element may also be commandwords (or control words) but have a different structure and/or protocolthan those issued by the guest. The different structure/protocol may bea new structure/protocol or may be an existing structure/protocol usedfor invoking maintenance or other service functions of the physicalchannel, for instance functions to alter and/or display values in memoryof the physical adapter. Existing unique command sets and buffermanagement protocols may exist to enable movement of data back and forthbetween the control element and a physical channel (physical HBA 226).These system control facilities may be different control facilities fromthose invoked by commands from a guest. In accordance with aspectsdescribed herein, requests from a control element may be used to invokesystem control facilities, of a physical channel, that perform the sameor similar functions as control facilities that a guest would invoke toactivate and initiate configuration of a virtual adapter.

Control element 232 can request the physical adapter to constructconfiguration information for a virtual HBA 228 that is not currentlyactivated (by a guest to which the virtual HBA is assigned). Theconfiguration information it represents is the configuration that wouldbe created for a virtual adapter after a guest boots and activates theadapter. The control element can invoke a procedure of the physicaladapter that causes the physical adapter to obtain, for a given virtualadapter, a WWPN that will become associated with that particular virtualadapter when a guest causes its activation.

The control element can also invoke functions to provide additionalconfiguration information after a guest has been brought online,activated the virtual adapter, and logged into to a fibre channelnetwork/device via that virtual adapter. Validation can be performedusing the control element after a guest is brought online. The controlelement may operate non-disruptive to the guest using the virtualadapter, requesting additional configuration information directly fromthe physical adapter after the guest is running and actively using thevirtual adapter. One benefit to the control component issuing requestsafter the guest is active is that it can provide additionalconfiguration information that is only available based on the guestbeing loaded. When a fibre channel ID is presented, it is implied thatthe guest is actively using the virtual HBA. In addition, other dynamicdata could be retrieved from the virtual HBA once it is in use by theguest.

The control element may activate and gather configuration informationfor any number of virtual HBAs that are hosted on a particular physicalHBA. The gathered information may be provided or exported for use byother processes and applications, administrators, or any other entity.In some examples, the information is used in establishing, verifying,validating, or debugging network component zoning, for instance SANzoning. In this regard, it can be determined whether the ascertainedconfiguration of a virtual adapter (for instance the assigned WWPN) isan appropriate virtual adapter configuration for the respective guestand, if not, the virtual adapter and/or network components may bereconfigured, all prior to activating the guest. This may prospectivelyfix problematic configurations before bringing any of the guests onlineand thereby more efficiently identify and address adaptermisconfigurations.

The configuration information obtained by the control element includes,in the examples above, a WWPN and a virtual fibre channel id. Otherconfiguration information may be obtained in order to ascertain otherconfigurations for the virtual adapters. For instance, the configurationinformation may include virtual adapter device numbers. When a virtualHBA, for instance, is allocated to a guest, a device number is allocatedto that the virtual adapter. The device number is an I/O subsystemconcept of numbering, analogous to virtual HBA numbering. The devicenumber uniquely identifies a virtual HBA number. A device number for avirtual adapter is available to an activated virtual adapter regardlessof whether the guest that is to use that virtual adapter is active.Validation can therefore be performed on all the device numbers that areavailable on a physical channel before these device numbers are assignedto the individual guests. Other fabric and remote N_Port data that canhelp in the diagnosis of various classes of issues may also be obtained.These might include performance information, event counters, and opticalpower information, among other information. Further exampleconfiguration information includes that which may be maintained incontrol blocks and obtained from a virtual HBA after issuing a requestto the virtual HBA, such as information indicating firmware version,protocol versions supported, data structure size limits, maximum datatransfer size, features supported by the virtual HBA, features supportedby host connection, fibre channel network topology, link speed, adaptertype, peer D_ID, number of status read buffers, local fibre channel portID, local and remote N_Port service parameters, number of ports,hardware version, hardware serial number, LOGI Accept Payload, andperformance data such as input requests, output requests, controlrequests, input megabytes, output megabytes, seconds since subchannelactivation, output megabytes, channel processor utilization, channel busutilization, and adapter utilization, as examples.

Aspects described above can be leveraged to facilitate determination andvalidation of access controls being enforced in controlling access bythe virtual HBAs to component(s) of a network to which the adapters areattached. Access controls may be those applied by the network (i.e.applied by components thereof, such as switches, firewalls, storagearrays, etc.). In the case of a storage area network, a network switchis typically configured for multiple zones. The adapters to use the SANdevices are assigned to these zones. If a virtual adapter is assigned toa particular zone, the virtual adapter will be able to access remoteN_ports in that zone. Conversely, a virtual adapter that is not part ofa given zone will not have access to N_ports of that zone. An N_port maybe a port of a storage device having a storage array. Fabric zoningtherefore may isolate adapters based on each of their assigned WWPNs, oron an N_Port basis, as examples, according to which storage arrays inthe SAN the adapters are to be able to access.

Within a storage array, logical units of storage are assigned logicalunit numbers (LUNs). LUN masking may be used to control which LUNs of astorage array are made available to each of the WWPNs. Validation ofaccess controls is the process of determining what access controls applyto control (i.e. allow or deny) adapter access to network component(s)and/or resources thereof. In the SAN content, validation might be usedto determine the LUNs to which a given guest has access and/or thezone(s) of which the guest is a member, and to validate that a givenguest has access (or is denied access) to the appropriate networkresources.

In some situations, determination of access controls being applied forcontrolling physical and virtual adapter access may be performedout-of-band, in which a separate link to a switch, storage array, orother network component is established and used to communicate with atarget component to obtain access control information, for instancezoning information in the case of a SAN. Example separate links includea separate Ethernet connection to a network fabric switch, or a tunnelto the command line interface or web interface of a storage device.These types of out-of-band determination of access control are not asrobust and reliable as performing in-band queries.

An example of in-band querying relies on a loaded guest of the hostsystem. One option is to have the guest using a virtual adapter issuequeries or other requests, obtain the responses, and then provideinformation back to an administrator. Access control validation in thesesituations is not being performed until the guest is booted and canissue requests to the physical adapter for sending into the network bythe virtual adapter. As described previously, a requirement that theguest be running to issue requests to obtain configuration informationmay be tedious and time-consuming, especially in the administration of anetwork in which there are tens or hundreds of devices accessing manynetwork components, with multiple administrators performing zoning andother access control setup and validation.

Consequently, and in accordance with further aspects described herein,the control element can, after activating a virtual adapter, use supportfacilities of the physical adapter to cause the activated virtualadapter to issue requests to network devices. The information obtainedbased on these requests can be used to determine access controls beingenforced for controlling access by the virtual adapter to networkcomponents.

The control element can use a request structure and protocol to initiatesending of requests by the activated virtual adapter. The requeststructure and protocol may be the same or different from the one usedabove to activate the virtual adapter and initiate construction of, e.g.the WWPN. The requests being sent by the virtual adapter may be the sameas, or similar to, those that a guest might cause the virtual adapter toissue after the guest is brought online.

In the SAN context, the control element can initiate sending of SAN anddevice I/O requests from the virtual adapter in order to probe and debugaccess control configurations of the SAN. This may be performed with orwithout the guest (to use that virtual adapter) currently executing. Insome embodiments, therefore, the control element can initially activatea virtual adapter absent any involvement of the guest, as above, andthen issue request(s) to the physical adapter to cause the activatedvirtual adapter to issue request(s) into the network. Such requestsissued into the network might include requests to log into the SAN andrequests to execute commands that probe for network access controlinformation, for instance indications as to what components the guesthas access to in the SAN. Zoning and LUN masking access controls, inaddition to other types of access controls, can be determined based onthe results of those requests. By way of further example, a controlelement could activate a virtual adapter and invoke a query through thatvirtual adapter to query the SAN to indicate what resources (forinstance N_ports) in the zone (to which the WWPN for the virtual adapteris assigned) are available to that virtual adapter. Once it is knownwhat N_ports are accessible to the virtual adapter, a particular N_portthat is accessible in the zone can be selected, and request(s) can besent to that N_port to probe for additional information, such as thetype of device to which the N_port belongs. The device could be astorage array of varying types offered by varying entities. An exampletype of storage array is the Enterprise Storage Server® (“D58000”)storage array offered by International Business Machines Corporation(Enterprise Storage Server® is a registered trademark of InternationalBusiness Machines Corporation, Armonk, N.Y.), thought other types ofstorage arrays are possible.

Once a type of device is determined, follow-up requests tailored to thatparticular type of device may be issued. For instance, requests can beissued to obtain link error statistics and node identifiers. In cases ofthe device having a storage array with one or more LUNs, a request tothe storage device can include a LUN interrogation request, such as aREPORT LUNS SCSI command in the case of a SCSI storage array. Thestorage device would respond to the LUN interrogation request byproviding back to the virtual adapter information that may then beprovided to the control element by the physical adapter and/or othercomponent of the I/O subsystem.

Processes are provided to enable a control element, such as one underdirection of an administrator or other user, to activate a virtual HBAand initiate the sending of requests by the virtual HBA to obtain accesscontrol information. These requests sent to components of the network bythe virtual HBA may be the same as or similar to commands that could beissued by the virtual HBA after a guest is booted. In some embodiments,these requests include, as discussed above, requests to a name server todiscover which remote N_ports are available to the guest in the zone towhich the guest belongs. The information returned from a networkcomponent to the virtual adapter (and therefore the physical adapterthat hosts the virtual adapter) in response can be provided to thecontrol element. The control element can also request that the virtualadapter perform activities to facilitate communication with the remoteN_ports, for instance setup structures to permit the virtual adapter tosubsequently talk to particular control units (e.g. storage arrays) towhich those remote N_ports correspond. Additionally, the control elementcan direct the virtual adapter to issue additional commands to furtherprobe network devices. Some or all of the information acquired by thevirtual adapter as a result of, and in response to, the issued requestscan be provided to the control element as access control information.The access control information may then be used to determine, by thecontrol element or a user, access controls being enforced by the network(e.g. components thereof) in controlling access by the virtual adapterto network components. The determined access controls, such as fabriczoning and LUN masking details, may be validated by the control elementor administrators, as examples.

As above, this validation can serve to trigger a reconfiguration of thevirtual adapter and/or network components, if appropriate. For instance,the control element or an administrator may determine, based on theobtained access control information access controls determinedtherefrom, whether the access controls are appropriate access controlsfor controlling access by the activated virtual adapter (and by proxy,the guest) to the network components. If not, the activated virtualadapter or a network component of the network may be reconfigured to fixthe erroneous access control being enforced. All of this may beperformed regardless of the state of the guest, for instance as theguest remains stopped or perhaps not even loaded into CEC memory. Insome instances, when the control element has gathered the desiredinformation after activating the adapter and invoking sending ofrequests therefrom, the control element may cause the physical adapterto return the virtual adapter to its state prior to the controlelement's activation thereof, for instance a deactivated ornon-configured state.

In some examples, the requests issued by the virtual adapter may be thesame as those that would be issued if triggered by a guest IPL, althoughthe manner used by the control element to initiate the sending of thoserequests may be different from the manner used by the guests to triggersending of those requests. Commands provided from the control element tothe physical channel may arrive through a different structure/protocolthan the commands issued by a guest to the physical channel, forinstance. Process thread(s) may execute on the physical channel andreceive service control word(s) from the control element. The thread(s)may then identify what the control element is attempting to invoke byits issuance of these service control words, translate that to requests(e.g. functions, operations, etc.) invocable by the virtual adapter, andthen cause the virtual adapter to issue those as requests to thenetwork. All of this may coexist with the physical and virtual adapters'abilities to service requests from the guest that is servicing thevirtual adapter. In other words, the initiating of the requests to besent, the sending of the requests, the receiving of responses, and theproviding of configuration information and access control informationback to the control element may all be performed non-disruptive to theguest's use of the virtual adapter to perform data input and output.Similarly, the guest's uses of the virtual adapter for data input andoutput may be non-disruptive to the management activities beingperformed by the control element.

FIG. 5 depicts an example in which a control element initiates sendingof requests by a virtual adapter into a storage area network, inaccordance with aspects described herein. As above with FIG. 4, acontrol element 232 is in communication with system 202 (physical serverin FIG. 5) that includes three inactive operating systems 224 and aphysical HBA 226 hosting three virtual HBAs 228 in this example. Thethree inactive OSs 224 may each be assigned a respective virtual HBA 228of the three virtual HBAs for use in performing data input and output,i.e. receiving data from, and sending data to, the network or othercomponents of the physical server. Each of the virtual HBAs 228 has arespective communication path to SAN components 230, which include afabric 234 that may include one or more fabric switches. Fabric 234 islogically and/or physically partitioned into multiple zones. In theexample of FIG. 5, fabric 234 is partitioned into zone A and zone B.Each zone is given access to a respective storage device 236, each ofwhich includes a storage array. Typically, a zone is given access to asingle (logical or physical) storage device and denied access to otherstorage devices, for instance those available to other zones.

Each storage device 236, corresponding to a respective zone in thisexample, is logically partitioned into logical units identified bylogical unit numbers (LUNs). This partitioning provides a way ofcontrolling which virtual adapters that are part of the same zone haveaccess to which logical storage units. LUN masking, in which a virtualadapter is given access to one or more LUNs of the array but deniedaccess to other LUNs of the array, provides a finer granularity ofcontrol than zoning typically provides.

The dashed path in FIG. 5 conceptually represents a path for issuingrequests to obtain access control information of SAN components 230.Initially, control element 232, running on a management control elementfor instance, can request physical HBA 226 to activate a virtual HBA 228as described above. The control element can also initiate sending ofrequests into the SAN. The control element may, as above, communicatewith the physical HBA via support facilities of physical server 202,such as one or more FSPs included therein. A request may be made fromthe control element 232 to physical HBA 226. The request may causephysical HBA 226 to construct appropriate requests (e.g. commands) to besent into the SAN via the activated virtual HBA. The requests are sentto/through fabric 234 in this example. Validation of access controls mayproceed incrementally by incrementally issuing requests that may or maynot be based on responses to previously issued requests. At eachincrement, information retrieved by, returned to, or determined by thevirtual adapter (or physical adapter) may be reported to the controlelement 232 and optionally used by the control element to determinefurther requests that the virtual adapter it to issue to the network.

By way of specific example, an initial request may be sent from thecontrol element to the physical adapter requesting that the virtualadapter be activated. The control element may then send one or morerequests to the physical adapter requesting that requests be sent fromthe virtual HBA into the network. An initial such request sent by thevirtual HBA can be to log the virtual HBA into the network fabric. Therequest may be sent to a fabric controller and request an indication ofwhich remote N_ports are accessible to the virtual adapter. A follow-uprequest may be made through the fabric to one of the remote N_ports, forinstance a remote N_port of a storage device 236, to determine whether alogin session on behalf of that virtual adapter can be completed. One ormore subsequent requests may be to query the storage device through thatremote N_port. An example such query may be a LUN interrogation request,such as a REPORT LUNS SCSI command, to request that the storage device'slogical unit inventory accessible to the virtual adapter be returned.The logical unit inventory may include a list including the LUNS of alllogical units accessible to the virtual adapter (and by proxy accessibleto the guest that is to use the virtual adapter when the guest isbrought online). Based on results of the LUN interrogation request,additional requests may be sent through fabric 234 and the N_port ofstorage device 236 to a particular LUN.

The above facilities enable in-band validation of access controls beingenforced from the point of the virtual HBA to the individual remote endpoints, including any intervening components. Since the requests beingissued are indistinguishable from those that would be issued after aguest is brought online, the same information obtainable by a guest maybe obtained by the control element without involvement of the guest andabsent any need for the guest to be brought online.

Data obtained from remote endpoints may be returned to the controlelement. This information can be used by administrators or other usersto establish and verify access controls being enforced to control accessby the virtual adapter (and by proxy the guest which is to use thatvirtual adapter, when it is brought online). In some embodiments, thecontrol element presents a graphical user interface that providesindications of some or all of the configuration information for avirtual adapter and the access controls being enforced. The presentedgraphical user interface may be presented as part of a web front-endwithin a browser running on the control element of a remote deviceaccessible to data provided by the control element.

The presented information may be organized in varying level of detail.The user interface may initially present a first level of information,such as the WWPNs and/or the device numbers assigned to each of thevirtual adapters within one or more CECs. This may be presented based onthe control element activating these virtual adapters and thatinformation being provided by the host system to the control element inresponse. Within this initial interface, a link may be provided toselect a WWPN of the presented WWPNs. At some time prior to, or basedon, selection of the WWPN, the control element may initiate the sendingof requests by the virtual adapter to network component(s). Forinstance, a request may be sent from the virtual adapter to a nameserver in a SAN. Based on receiving that request, the name server mayprovide access control information back to the virtual adapter, whichmay then be provided by the physical adapter or another component of thehost system to control element for presentation in the user interface.The returned access control information may include a listing of allremote N_ports (corresponding to different storage arrays, for instance)available in the zone to which the WWPN is given access. The interfacemay present this information and enable a user to select a remoteN_port. At some time prior to, or based on, selection of the remoteN_port, the control element may initiate the sending of request(s) bythe virtual adapter to the N_port to obtain access control informationindicating LUNs to which the selected WWPN has access. Going further,requests may be issued by the virtual HBA, based on invocation by thecontrol element, to query for information including node identifiers andlink error status blocks, as examples.

The structure, format, arrangement, and other properties of the requestsbeing sent by a virtual adapter may be dictated by the particularitiesof the network to which the virtual adapter is attached. Suchparticularities include the type of network (such as switched fabric,point-to-point, Arbitrated loop, etc) and the protocol used to talk tothe network devices. In a fibre channel network, for instance, the fibrechannel protocol would dictate the specifics of the requests beingissued.

Described above are facilities that enable, for instance, mappingconfiguration information and resource availability for virtual adaptersthat are to be used by virtual guests of a host system. Thesefacilitates are enabled absent any need for the guests to be running andabsent any need for guest or hypervisor intervention.

Accordingly, aspects described herein provide processes for ascertainingconfiguration of a virtual adapter. An example such process is describedand depicted with reference to FIG. 6. The process of FIG. 6 may beperformed at least partially by a control component of a computingenvironment as described herein.

The process begins by activating a virtual adapter (602) of a computingenvironment. The virtual adapter may be hosted on a physical adapter ofa host system of the computing environment and may be for use by a guestof that host system in performing data input and output. In particularembodiments, the physical adapter may include a physical fibre channeladapter and the activated virtual adapter may be a virtual fibre channeladapter hosted on the physical fibre channel adapter.

The activating may be by a control component, such as a control element,of the computing environment. The activating may be performed by way ofthe control component providing a request to the physical adapter thatthe virtual adapter be activated and configured. The request that thevirtual adapter be activated can be provided to the physical adapter viaa system control facility of the physical adapter. The system controlfacility may be a management control facility that is different from acontrol facility that the guest may use to activate the virtual adapter.

Further, the activating can activate the virtual adapter absentinvolvement of the guest. Yet further, the guest may remain inactiveduring the activating of the virtual adapter. For instance, theactivating of the virtual adapter may occur while the guest is stopped,prior to an initial program load of the guest.

The control component may be a separate system from the host system. Insome embodiments, the host system executes on a first set ofprocessor(s) and the control component executes on a second set ofprocessor(s) that are different from the first set of processor(s).

Continuing with the process of FIG. 6, based on activating the virtualadapter, the control component may obtain configuration information ofthe activated virtual adapter (604). The configuration information maybe obtained from the physical adapter and be generated based on theactivating by the control component. The activating may invokeconfiguration of the virtual adapter to be performed by the physicaladapter. As part of this configuration, a world wide port name may beassigned for the activated virtual adapter. The configurationinformation obtained by the control component can include this worldwide port name for the activated virtual adapter.

The process continues by ascertaining, by the control component, aconfiguration of the activated virtual adapter (606) based on theobtained configuration information. For instance, when the configurationinformation indicates a world wide port name for the virtual adapter,the ascertaining may include the control component determining what theworld wide port name is for that adapter.

Continuing with FIG. 6, is then determined whether the configuration ofthe activated virtual adapter is an appropriate virtual adapterconfiguration for the guest (608). This may be based on, for instance,user policies or desires regarding how the virtual adapter is to beconfigured. This determining may be performed while the guest remainsinactive. If it is determined that the configuration is not anappropriate virtual adapter configuration for the guest, the processproceeds by reconfiguring the activated virtual adapter (610). In someexamples, this is performed automatically by a component, such as thecontrol component, having the ability to reconfigure the physicaladapter or other aspects of the host system prior to activating theguest. In other examples, the reconfiguration may be effected by anadministrator or other user.

The reconfiguration may require that the virtual adapter be deactivated.In any case, the above process may be repeated to again ascertain aconfiguration of the virtual adapter, i.e. to verify that thereconfiguration has resulted in an appropriate configuration for thevirtual adapter. If the virtual adapter is to be reactivated, then, asdepicted in FIG. 6, the process returns to perform activation of thevirtual adapter (602), otherwise the process may return directly to(604) in cases where the reconfiguring was performed as the adapterremained activated.

Returning to (608), if the configuration is appropriate, and optionallyin some embodiments, subsequent to the activation of the guest, thecontrol component requests from the physical adapter additionalconfiguration information of the activated virtual adapter, and obtainsthe additional configuration information based on that requesting (612).Additional configuration of the activated virtual adapter may beascertained based on the obtained additional configuration information.In some examples, this additional configuration information is requestedafter the guest has been activated (i.e. when it is running, after aninitial program load). The guest may also be actively using the virtualadapter. The requesting of the additional configuration information andthe receiving of the additional configuration information by the controlcomponent from the physical adapter may be non-disruptive of use of theactivated virtual adapter by the guest in performing data input andoutput. Furthermore, the guest may use the activated virtual adapter inperforming data input and output non-disruptive of the requesting andthe receiving of this additional configuration information by thecontrol component.

Some or all aspects of FIG. 6 may be performed by the control componentabsent any communication between the control component and the guest. Insome cases, the process of FIG. 6 is performed for multiple virtualadapters hosted on one or more physical adapters, with each virtualadapter of the plurality of virtual adapters being provided for arespective guest of a plurality of guests of the host system. All orsome of the guests may remain inactive during this process.

In addition to the process of FIG. 6 for ascertaining configuration of avirtual adapter based on being activated by a control component, in-banddetermination and validation of access controls is provided according toaspects described herein. FIG. 7 depicts an example process fordetermining access controls being enforced by a network in controllingaccess by an activated virtual adapter to components of the network. Theprocess of FIG. 7 may be performed at least partially by a controlcomponent of a computing environment as described herein.

The process begins by the control component of the computing environmentinitiating sending of requests (commands in this example) over a networkof the computing environment by an activated virtual adapter (702). Theactivated virtual adapter may be activated as described above. It may behosted on a physical adapter of a host system coupled to the network andmay be for use by a guest hosted by the host system in performing datainput and output.

The sent requests retrieve access control information from the network.The access control information is indicative of access control(s)enforced by the network (i.e. component(s) thereof) in controllingaccess by the activated virtual adapter to network component(s) of thenetwork. Controlling access may refer to allowing access or denyingaccess. Thus, the access controls may enable or prevent access by theactivated virtual adapter to at least some network components.

Initiating in this context may include the control component providingindication(s) to the physical adapter that the requests be sent by thevirtual adapter. This initiating may be performed absent any involvementof the guest that is to use the virtual adapter for data I/O.

Based on the initiating, the control component obtains the accesscontrol information from (704) the physical adapter. For instance,responses to the requests sent into the network may be received by thevirtual adapter and information thereof may be provided to, and obtainedby, the control element. The control component can determine, based onthat information, the one or more access controls being enforced by thenetwork in controlling access by the activated virtual adapter to theone or more network components (706).

In some specific embodiments, the initiating initiates sending of arequest to log the activated virtual adapter into the network. Based onlogging the virtual adapter into the network, the initiating may alsoinitiate sending of a request to determine remote ports of the networkthat are accessible to the activated virtual adapter. The retrievedaccess control information may indicate/identify the remote port(s) ofthe network that are accessible to the activated virtual adapter. Theinitiating may also initiate sending a request to log into a remote portof the indicated remote port(s) accessible to the activated virtualadapter.

The one or more network components may be components of a storage areanetwork and the remote port may be a remote port of a storage devicehosting a storage array. A logical unit of the storage array may beindicated by a logical unit number that may be retrieved as part of theretrieved access control information. Additionally or alternatively, theretrieved access control information may include logical unit numbermasking data or zoning configuration data for controlling zones of thestorage area network. The determining of the access controls maydetermine one or more storage arrays to which the activated virtualadapter has access, or determine one or more zones of which theactivated virtual adapter is a member. Additionally, a request of theinitiated requests may include a logical unit number interrogationrequest to interrogate a storage array with which an accessible remoteport is associated.

Based on at least some of the obtained access control information, itmay be determined whether the access controls represent an appropriateconfiguration for controlling access by the activated virtual adapter tothe one or more network components (708). This is may be effected bycomparing a set of desired or modeled access controls to the determinedone or more access controls being enforced. If it is determined that theconfiguration is inappropriate, the activated virtual adapter and/ornetwork component(s) of the network may be reconfigured (710). In someexamples, as before, this may be performed automatically by a component,such as the control component, or by an administrator or other user.Also as above, this reconfiguration may require that the virtual adapterand/or other network components be deactivated. In any case, the processof FIG. 7 may be repeated, optionally after reactivating the virtualadapter (see FIG. 6). Thus, the process may return to (702) to againinitiate sending of commands by the virtual adapter.

Returning to (708), if the configuration is appropriate, then theprocess ends. All, some, or none of the aspects of FIG. 7 may beperformed while the guest remains inactive, prior to an initial programload of the guest.

Additionally, the aspects of FIG. 7 may all be performed by the controlcomponent absent any communication between the control component and theguest. In some cases, the process of FIG. 7 is performed for multiplevirtual adapters hosted on one or more physical adapters, with eachvirtual adapter of the plurality of virtual adapters being provided fora respective guest of a plurality of guests of the host system. All orsome of the guests may remain inactive during this process.

Also as above, in cases where the guest is active for some or all of theprocess of FIG. 7, the guest may also be actively using the virtualadapter. The processing of FIG. 7 by the control component (e.g. theinitiating, obtaining, and determining) may be non-disruptive of use ofthe activated virtual adapter by the guest in performing data input andoutput. Furthermore, the guest may use the activated virtual adapter inperforming data input and output non-disruptive of this processing bythe control component.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention. Referring to FIG. 8, in one example, a computerprogram product 800 includes, for instance, one or more non-transitorycomputer readable storage media 802 to store computer readable programcode means, logic and/or instructions 804 thereon to provide andfacilitate one or more embodiments.

A computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

In addition to the above, one or more aspects may be provided, offered,deployed, managed, serviced, etc. by a service provider who offersmanagement of customer environments. For instance, the service providercan create, maintain, support, etc. computer code and/or a computerinfrastructure that performs one or more aspects for one or morecustomers. In return, the service provider may receive payment from thecustomer under a subscription and/or fee agreement, as examples.Additionally or alternatively, the service provider may receive paymentfrom the sale of advertising content to one or more third parties.

In one aspect, an application may be deployed for performing one or moreembodiments. As one example, the deploying of an application comprisesproviding computer infrastructure operable to perform one or moreembodiments.

As a further aspect, a computing infrastructure may be deployedcomprising integrating computer readable code into a computing system,in which the code in combination with the computing system is capable ofperforming one or more embodiments.

As yet a further aspect, a process for integrating computinginfrastructure comprising integrating computer readable code into acomputer system may be provided. The computer system comprises acomputer readable medium, in which the computer medium comprises one ormore embodiments. The code in combination with the computer system iscapable of performing one or more embodiments.

Although various embodiments are described above, these are onlyexamples. For example, computing environments of other architectures canbe used to incorporate and use one or more embodiments. Further,different instructions, instruction formats, instruction fields and/orinstruction values may be used. Yet further, other limits may beprovided and/or used in differing ways. Many variations are possible.

Further, other types of computing environments can benefit and be used.As an example, a data processing system suitable for storing and/orexecuting program code is usable that includes at least two processorscoupled directly or indirectly to memory elements through a system bus.The memory elements include, for instance, local memory employed duringactual execution of the program code, bulk storage, and cache memorywhich provide temporary storage of at least some program code in orderto reduce the number of times code must be retrieved from bulk storageduring execution.

Input/Output or I/O devices (including, but not limited to, keyboards,displays, pointing devices, DASD, tape, CDs, DVDs, thumb drives andother memory media, etc.) can be coupled to the system either directlyor through intervening I/O controllers. Network adapters may also becoupled to the system to enable the data processing system to becomecoupled to other data processing systems or remote printers or storagedevices through intervening private or public networks. Modems, cablemodems, and Ethernet cards are just a few of the available types ofnetwork adapters.

Referring to FIG. 9, representative components of a Host Computer system900 to implement one or more embodiments are portrayed. Therepresentative host computer 900 comprises one or more CPUs 901 incommunication with computer memory (i.e., central storage) 902, as wellas I/O interfaces to storage media devices 911 and networks 910 forcommunicating with other computers or SANs and the like. The CPU 901 iscompliant with an architecture having an architected instruction set andarchitected functionality. The CPU 901 may have access registertranslation (ART) 912, which includes an ART lookaside buffer (ALB) 913,for selecting an address space to be used by dynamic address translation(DAT) 903 for transforming program addresses (virtual addresses) intoreal addresses of memory. A DAT typically includes a translationlookaside buffer (TLB) 907 for caching translations so that lateraccesses to the block of computer memory 902 do not require the delay ofaddress translation. Typically, a cache 909 is employed between computermemory 902 and the processor 901. The cache 909 may be hierarchicalhaving a large cache available to more than one CPU and smaller, faster(lower level) caches between the large cache and each CPU. In someimplementations, the lower level caches are split to provide separatelow level caches for instruction fetching and data accesses.

In one embodiment, an instruction is fetched from memory 902 by aninstruction fetch unit 904 via a cache 909. The instruction is decodedin an instruction decode unit 906 and dispatched (with otherinstructions in some embodiments) to instruction execution unit or units908. Typically several execution units 908 are employed, for example anarithmetic execution unit, a floating point execution unit and a branchinstruction execution unit. The instruction is executed by the executionunit, accessing operands from instruction specified registers or memoryas needed. If an operand is to be accessed (loaded or stored) frommemory 902, a load/store unit 905 typically handles the access undercontrol of the instruction being executed. Instructions may be executedin hardware circuits or in internal microcode (firmware) or by acombination of both.

As noted, a computer system includes information in local (or main)storage, as well as addressing, protection, and reference and changerecording. Some aspects of addressing include the format of addresses,the concept of address spaces, the various types of addresses, and themanner in which one type of address is translated to another type ofaddress. Some of main storage includes permanently assigned storagelocations. Main storage provides the system with directly addressablefast-access storage of data. Both data and programs are to be loadedinto main storage (from input devices) before they can be processed.

Main storage may include one or more smaller, faster-access bufferstorages, sometimes called caches. A cache is typically physicallyassociated with a CPU or an I/O processor. The effects, except onperformance, of the physical construction and use of distinct storagemedia are generally not observable by the program.

Separate caches may be maintained for instructions and for dataoperands. Information within a cache is maintained in contiguous byteson an integral boundary called a cache block or cache line (or line, forshort).

Storage is viewed as a long horizontal string of bits. For mostoperations, accesses to storage proceed in a left-to-right sequence. Thestring of bits is subdivided into units of eight bits. An eight-bit unitis called a byte, which is the basic building block of all informationformats. Each byte location in storage is identified by a uniquenonnegative integer, which is the address of that byte location or,simply, the byte address. Adjacent byte locations have consecutiveaddresses, starting with 0 on the left and proceeding in a left-to-rightsequence. Addresses are unsigned binary integers and are 24, 31, or 64bits.

Information is transmitted between storage and a CPU or a channelsubsystem one byte, or a group of bytes, at a time. Unless otherwisespecified, in, for instance, the z/Architecture, a group of bytes instorage is addressed by the leftmost byte of the group. The number ofbytes in the group is either implied or explicitly specified by theoperation to be performed. When used in a CPU operation, a group ofbytes is called a field. Within each group of bytes, in, for instance,the z/Architecture, bits are numbered in a left-to-right sequence. Inthe z/Architecture, the leftmost bits are sometimes referred to as the“high-order” bits and the rightmost bits as the “low-order” bits. Bitnumbers are not storage addresses, however. Only bytes can be addressed.To operate on individual bits of a byte in storage, the entire byte isaccessed. The bits in a byte are numbered 0 through 7, from left toright (in, e.g., the z/Architecture). The bits in an address may benumbered 8-31 or 40-63 for 24-bit addresses, or 1-31 or 33-63 for 31-bitaddresses; they are numbered 0-63 for 64-bit addresses. In one example,bits 8-31 and 1-31 apply to addresses that are in a location (e.g.,register) that is 32 bits wide, whereas bits 40-63 and 33-63 apply toaddresses that are in a 64-bit wide location. Within any otherfixed-length format of multiple bytes, the bits making up the format areconsecutively numbered starting from 0. For purposes of error detection,and preferably for correction, one or more check bits may be transmittedwith each byte or with a group of bytes. Such check bits are generatedautomatically by the machine and cannot be directly controlled by theprogram. Storage capacities are expressed in number of bytes. When thelength of a storage-operand field is implied by the operation code of aninstruction, the field is said to have a fixed length, which can be one,two, four, eight, or sixteen bytes. Larger fields may be implied forsome instructions. When the length of a storage-operand field is notimplied but is stated explicitly, the field is said to have a variablelength. Variable-length operands can vary in length by increments of onebyte (or with some instructions, in multiples of two bytes or othermultiples). When information is placed in storage, the contents of onlythose byte locations are replaced that are included in the designatedfield, even though the width of the physical path to storage may begreater than the length of the field being stored.

Certain units of information are to be on an integral boundary instorage. A boundary is called integral for a unit of information whenits storage address is a multiple of the length of the unit in bytes.Special names are given to fields of 2, 4, 8, 16, and 32 bytes on anintegral boundary. A halfword is a group of two consecutive bytes on atwo-byte boundary and is the basic building block of instructions. Aword is a group of four consecutive bytes on a four-byte boundary. Adoubleword is a group of eight consecutive bytes on an eight-byteboundary. A quadword is a group of 16 consecutive bytes on a 16-byteboundary. An octoword is a group of 32 consecutive bytes on a 32-byteboundary. When storage addresses designate halfwords, words,doublewords, quadwords, and octowords, the binary representation of theaddress contains one, two, three, four, or five rightmost zero bits,respectively. Instructions are to be on two-byte integral boundaries.The storage operands of most instructions do not have boundary-alignmentrequirements.

On devices that implement separate caches for instructions and dataoperands, a significant delay may be experienced if the program storesinto a cache line from which instructions are subsequently fetched,regardless of whether the store alters the instructions that aresubsequently fetched.

In one example, the embodiment may be practiced by software (sometimesreferred to licensed internal code, firmware, micro-code, milli-code,pico-code and the like, any of which would be consistent with one ormore embodiments). Referring to FIG. 9, software program code whichembodies one or more aspects may be accessed by processor 901 of thehost system 900 from long-term storage media devices 911, such as aCD-ROM drive, tape drive or hard drive. The software program code may beembodied on any of a variety of known media for use with a dataprocessing system, such as a diskette, hard drive, or CD-ROM. The codemay be distributed on such media, or may be distributed to users fromcomputer memory 902 or storage of one computer system over a network 910to other computer systems for use by users of such other systems.

The software program code includes an operating system which controlsthe function and interaction of the various computer components and oneor more application programs. Program code is normally paged fromstorage media device 911 to the relatively higher-speed computer storage902 where it is available for processing by processor 901. Thetechniques and methods for embodying software program code in memory, onphysical media, and/or distributing software code via networks are wellknown and will not be further discussed herein. Program code, whencreated and stored on a tangible medium (including but not limited toelectronic memory modules (RAM), flash memory, Compact Discs (CDs),DVDs, Magnetic Tape and the like is often referred to as a “computerprogram product”. The computer program product medium is typicallyreadable by a processing circuit preferably in a computer system forexecution by the processing circuit.

FIG. 10 illustrates a representative workstation or server hardwaresystem in which one or more embodiments may be practiced. The system 920of FIG. 10 comprises a representative base computer system 921, such asa personal computer, a workstation or a server, including optionalperipheral devices. The base computer system 921 includes one or moreprocessors 926 and a bus employed to connect and enable communicationbetween the processor(s) 926 and the other components of the system 921in accordance with known techniques. The bus connects the processor 926to memory 925 and long-term storage 927 which can include a hard drive(including any of magnetic media, CD, DVD and Flash Memory for example)or a tape drive for example. The system 921 might also include a userinterface adapter, which connects the microprocessor 926 via the bus toone or more interface devices, such as a keyboard 924, a mouse 923, aprinter/scanner 930 and/or other interface devices, which can be anyuser interface device, such as a touch sensitive screen, digitized entrypad, etc. The bus also connects a display device 922, such as an LCDscreen or monitor, to the microprocessor 926 via a display adapter.

The system 921 may communicate with other computers or networks ofcomputers by way of a network adapter capable of communicating 928 witha network 929. Example network adapters are communications channels,token ring, Ethernet or modems. Alternatively, the system 921 maycommunicate using a wireless interface, such as a CDPD (cellular digitalpacket data) card. The system 921 may be associated with such othercomputers in a Local Area Network (LAN) or a Wide Area Network (WAN), orthe system 921 can be a client in a client/server arrangement withanother computer, etc. All of these configurations, as well as theappropriate communications hardware and software, are known in the art.

FIG. 11 illustrates a data processing network 940 in which one or moreembodiments may be practiced. The data processing network 940 mayinclude a plurality of individual networks, such as a wireless networkand a wired network, each of which may include a plurality of individualworkstations 941, 942, 943, 944. Additionally, as those skilled in theart will appreciate, one or more LANs may be included, where a LAN maycomprise a plurality of intelligent workstations coupled to a hostprocessor.

Still referring to FIG. 11, the networks may also include mainframecomputers or servers, such as a gateway computer (client server 946) orapplication server (remote server 948 which may access a data repositoryand may also be accessed directly from a workstation 945). A gatewaycomputer 946 serves as a point of entry into each individual network. Agateway is needed when connecting one networking protocol to another.The gateway 946 may be preferably coupled to another network (theInternet 947 for example) by means of a communications link. The gateway946 may also be directly coupled to one or more workstations 941, 942,943, 944 using a communications link. The gateway computer may beimplemented utilizing an IBM eServer System z server available fromInternational Business Machines Corporation.

Referring concurrently to FIG. 10 and FIG. 11, software programming code931 which may embody one or more aspects may be accessed by theprocessor 926 of the system 920 from long-term storage media 927, suchas a CD-ROM drive or hard drive. The software programming code may beembodied on any of a variety of known media for use with a dataprocessing system, such as a diskette, hard drive, or CD-ROM. The codemay be distributed on such media, or may be distributed to users 950,951 from the memory or storage of one computer system over a network toother computer systems for use by users of such other systems.

Alternatively, the programming code may be embodied in the memory 925,and accessed by the processor 926 using the processor bus. Suchprogramming code includes an operating system which controls thefunction and interaction of the various computer components and one ormore application programs 932. Program code is normally paged fromstorage media 927 to high-speed memory 925 where it is available forprocessing by the processor 926. The techniques and methods forembodying software programming code in memory, on physical media, and/ordistributing software code via networks are well known and will not befurther discussed herein. Program code, when created and stored on atangible medium (including but not limited to electronic memory modules(RAM), flash memory, Compact Discs (CDs), DVDs, Magnetic Tape and thelike is often referred to as a “computer program product”. The computerprogram product medium is typically readable by a processing circuitpreferably in a computer system for execution by the processing circuit.

The cache that is most readily available to the processor (normallyfaster and smaller than other caches of the processor) is the lowest (L1or level one) cache and main store (main memory) is the highest levelcache (L3 if there are 3 levels). The lowest level cache is oftendivided into an instruction cache (I-Cache) holding machine instructionsto be executed and a data cache (D-Cache) holding data operands.

Referring to FIG. 12, an exemplary processor embodiment is depicted forprocessor 926. Typically one or more levels of cache 953 are employed tobuffer memory blocks in order to improve processor performance. Thecache 953 is a high speed buffer holding cache lines of memory data thatare likely to be used. Typical cache lines are 64, 128 or 256 bytes ofmemory data. Separate caches are often employed for caching instructionsthan for caching data. Cache coherence (synchronization of copies oflines in memory and the caches) is often provided by various “snoop”algorithms well known in the art. Main memory storage 925 of a processorsystem is often referred to as a cache. In a processor system having 4levels of cache 953, main storage 925 is sometimes referred to as thelevel 5 (L5) cache since it is typically faster and only holds a portionof the non-volatile storage (DASD, tape etc) that is available to acomputer system. Main storage 925 “caches” pages of data paged in andout of the main storage 925 by the operating system.

A program counter (instruction counter) 961 keeps track of the addressof the current instruction to be executed. A program counter in az/Architecture processor is 64 bits and can be truncated to 31 or 24bits to support prior addressing limits. A program counter is typicallyembodied in a PSW (program status word) of a computer such that itpersists during context switching. Thus, a program in progress, having aprogram counter value, may be interrupted by, for example, the operatingsystem (context switch from the program environment to the operatingsystem environment). The PSW of the program maintains the programcounter value while the program is not active, and the program counter(in the PSW) of the operating system is used while the operating systemis executing. Typically, the program counter is incremented by an amountequal to the number of bytes of the current instruction. RISC (ReducedInstruction Set Computing) instructions are typically fixed length whileCISC (Complex Instruction Set Computing) instructions are typicallyvariable length. Instructions of the IBM z/Architecture are CISCinstructions having a length of 2, 4 or 6 bytes. The Program counter 961is modified by either a context switch operation or a branch takenoperation of a branch instruction for example. In a context switchoperation, the current program counter value is saved in the programstatus word along with other state information about the program beingexecuted (such as condition codes), and a new program counter value isloaded pointing to an instruction of a new program module to beexecuted. A branch taken operation is performed in order to permit theprogram to make decisions or loop within the program by loading theresult of the branch instruction into the program counter 5061.

Typically an instruction fetch unit 955 is employed to fetchinstructions on behalf of the processor 926. The fetch unit eitherfetches “next sequential instructions”, target instructions of branchtaken instructions, or first instructions of a program following acontext switch. Modern Instruction fetch units often employ prefetchtechniques to speculatively prefetch instructions based on thelikelihood that the prefetched instructions might be used. For example,a fetch unit may fetch 16 bytes of instruction that includes the nextsequential instruction and additional bytes of further sequentialinstructions.

The fetched instructions are then executed by the processor 926. In anembodiment, the fetched instruction(s) are passed to a dispatch unit 956of the fetch unit. The dispatch unit decodes the instruction(s) andforwards information about the decoded instruction(s) to appropriateunits 957, 958, 960. An execution unit 957 will typically receiveinformation about decoded arithmetic instructions from the instructionfetch unit 955 and will perform arithmetic operations on operandsaccording to the opcode of the instruction. Operands are provided to theexecution unit 957 preferably either from memory 925, architectedregisters 959 or from an immediate field of the instruction beingexecuted. Results of the execution, when stored, are stored either inmemory 925, registers 959 or in other machine hardware (such as controlregisters, PSW registers and the like).

Virtual addresses are transformed into real addresses using dynamicaddress translation 962 and, optionally, using access registertranslation 963.

A processor 926 typically has one or more units 957, 958, 960 forexecuting the function of the instruction. Referring to FIG. 13A, anexecution unit 957 may communicate 971 with architected generalregisters 959, a decode/dispatch unit 956, a load store unit 960, andother 965 processor units by way of interfacing logic 971. An executionunit 957 may employ several register circuits 967, 968, 969 to holdinformation that the arithmetic logic unit (ALU) 966 will operate on.The ALU performs arithmetic operations such as add, subtract, multiplyand divide as well as logical function such as and, or and exclusive-or(XOR), rotate and shift. Preferably the ALU supports specializedoperations that are design dependent. Other circuits may provide otherarchitected facilities 972 including condition codes and recoverysupport logic for example. Typically the result of an ALU operation isheld in an output register circuit 970 which can forward the result to avariety of other processing functions. There are many arrangements ofprocessor units, the present description is only intended to provide arepresentative understanding of one embodiment.

An ADD instruction for example would be executed in an execution unit957 having arithmetic and logical functionality while a floating pointinstruction for example would be executed in a floating point executionhaving specialized floating point capability. Preferably, an executionunit operates on operands identified by an instruction by performing anopcode defined function on the operands. For example, an ADD instructionmay be executed by an execution unit 957 on operands found in tworegisters 959 identified by register fields of the instruction.

The execution unit 957 performs the arithmetic addition on two operandsand stores the result in a third operand where the third operand may bea third register or one of the two source registers. The execution unitpreferably utilizes an Arithmetic Logic Unit (ALU) 966 that is capableof performing a variety of logical functions such as Shift, Rotate, And,Or and XOR as well as a variety of algebraic functions including any ofadd, subtract, multiply, divide. Some ALUs 966 are designed for scalaroperations and some for floating point. Data may be Big Endian (wherethe least significant byte is at the highest byte address) or LittleEndian (where the least significant byte is at the lowest byte address)depending on architecture. The IBM z/Architecture is Big Endian. Signedfields may be sign and magnitude, 1's complement or 2's complementdepending on architecture. A 2's complement number is advantageous inthat the ALU does not need to design a subtract capability since eithera negative value or a positive value in 2's complement requires only anaddition within the ALU. Numbers are commonly described in shorthand,where a 12 bit field defines an address of a 4,096 byte block and iscommonly described as a 4 Kbyte (Kilo-byte) block, for example.

Referring to FIG. 13B, branch instruction information for executing abranch instruction is typically sent to a branch unit 958 which oftenemploys a branch prediction algorithm such as a branch history table5082 to predict the outcome of the branch before other conditionaloperations are complete. The target of the current branch instructionwill be fetched and speculatively executed before the conditionaloperations are complete. When the conditional operations are completedthe speculatively executed branch instructions are either completed ordiscarded based on the conditions of the conditional operation and thespeculated outcome. A typical branch instruction may test conditioncodes and branch to a target address if the condition codes meet thebranch requirement of the branch instruction, a target address may becalculated based on several numbers including ones found in registerfields or an immediate field of the instruction for example. The branchunit 958 may employ an ALU 974 having a plurality of input registercircuits 975, 976, 977 and an output register circuit 980. The branchunit 958 may communicate 981 with general registers 959, decode dispatchunit 956 or other circuits 973, for example.

The execution of a group of instructions can be interrupted for avariety of reasons including a context switch initiated by an operatingsystem, a program exception or error causing a context switch, an I/Ointerruption signal causing a context switch or multi-threading activityof a plurality of programs (in a multi-threaded environment), forexample. Preferably a context switch action saves state informationabout a currently executing program and then loads state informationabout another program being invoked. State information may be saved inhardware registers or in memory for example. State informationpreferably comprises a program counter value pointing to a nextinstruction to be executed, condition codes, memory translationinformation and architected register content. A context switch activitycan be exercised by hardware circuits, application programs, operatingsystem programs or firmware code (microcode, pico-code or licensedinternal code (LIC)) alone or in combination.

A processor accesses operands according to instruction defined methods.The instruction may provide an immediate operand using the value of aportion of the instruction, may provide one or more register fieldsexplicitly pointing to either general purpose registers or specialpurpose registers (floating point registers for example). Theinstruction may utilize implied registers identified by an opcode fieldas operands. The instruction may utilize memory locations for operands.A memory location of an operand may be provided by a register, animmediate field, or a combination of registers and immediate field asexemplified by the z/Architecture long displacement facility wherein theinstruction defines a base register, an index register and an immediatefield (displacement field) that are added together to provide theaddress of the operand in memory for example. Location herein typicallyimplies a location in main memory (main storage) unless otherwiseindicated.

Referring to FIG. 13C, a processor accesses storage using a load/storeunit 960. The load/store unit 960 may perform a load operation byobtaining the address of the target operand in memory 953 and loadingthe operand in a register 959 or another memory 953 location, or mayperform a store operation by obtaining the address of the target operandin memory 953 and storing data obtained from a register 959 or anothermemory 953 location in the target operand location in memory 953. Theload/store unit 960 may be speculative and may access memory in asequence that is out-of-order relative to instruction sequence, howeverthe load/store unit 960 is to maintain the appearance to programs thatinstructions were executed in order. A load/store unit 960 maycommunicate 984 with general registers 959, decode/dispatch unit 956,cache/memory interface 953 or other elements 983 and comprises variousregister circuits 986, 987, 988 and 989, ALUs 985 and control logic 990to calculate storage addresses and to provide pipeline sequencing tokeep operations in-order. Some operations may be out of order but theload/store unit provides functionality to make the out of orderoperations to appear to the program as having been performed in order,as is well known in the art.

Preferably addresses that an application program “sees” are oftenreferred to as virtual addresses. Virtual addresses are sometimesreferred to as “logical addresses” and “effective addresses”. Thesevirtual addresses are virtual in that they are redirected to physicalmemory location by one of a variety of dynamic address translation (DAT)technologies including, but not limited to, simply prefixing a virtualaddress with an offset value, translating the virtual address via one ormore translation tables, the translation tables preferably comprising atleast a segment table and a page table alone or in combination,preferably, the segment table having an entry pointing to the pagetable. In the z/Architecture, a hierarchy of translation is providedincluding a region first table, a region second table, a region thirdtable, a segment table and an optional page table. The performance ofthe address translation is often improved by utilizing a translationlookaside buffer (TLB) which comprises entries mapping a virtual addressto an associated physical memory location. The entries are created whenthe DAT translates a virtual address using the translation tables.Subsequent use of the virtual address can then utilize the entry of thefast TLB rather than the slow sequential translation table accesses. TLBcontent may be managed by a variety of replacement algorithms includingLRU (Least Recently used).

In the case where the processor is a processor of a multi-processorsystem, each processor has responsibility to keep shared resources, suchas I/O, caches, TLBs and memory, interlocked for coherency. Typically,“snoop” technologies will be utilized in maintaining cache coherency. Ina snoop environment, each cache line may be marked as being in any oneof a shared state, an exclusive state, a changed state, an invalid stateand the like in order to facilitate sharing.

I/O units 954 (FIG. 11) provide the processor with means for attachingto peripheral devices including tape, disc, printers, displays, andnetworks for example. I/O units are often presented to the computerprogram by software drivers. In mainframes, such as the System z fromIBM®, channel adapters and open system adapters are I/O units of themainframe that provide the communications between the operating systemand peripheral devices.

Further, other types of computing environments can benefit from one ormore aspects. As an example, an environment may include an emulator(e.g., software or other emulation mechanisms), in which a particulararchitecture (including, for instance, instruction execution,architected functions, such as address translation, and architectedregisters) or a subset thereof is emulated (e.g., on a native computersystem having a processor and memory). In such an environment, one ormore emulation functions of the emulator can implement one or moreembodiments, even though a computer executing the emulator may have adifferent architecture than the capabilities being emulated. As oneexample, in emulation mode, the specific instruction or operation beingemulated is decoded, and an appropriate emulation function is built toimplement the individual instruction or operation.

In an emulation environment, a host computer includes, for instance, amemory to store instructions and data; an instruction fetch unit tofetch instructions from memory and to optionally, provide localbuffering for the fetched instruction; an instruction decode unit toreceive the fetched instructions and to determine the type ofinstructions that have been fetched; and an instruction execution unitto execute the instructions. Execution may include loading data into aregister from memory; storing data back to memory from a register; orperforming some type of arithmetic or logical operation, as determinedby the decode unit. In one example, each unit is implemented insoftware. For instance, the operations being performed by the units areimplemented as one or more subroutines within emulator software.

More particularly, in a mainframe, architected machine instructions areused by programmers, usually today “C” programmers, often by way of acompiler application. These instructions stored in the storage mediummay be executed natively in a z/Architecture IBM® Server, oralternatively in machines executing other architectures. They can beemulated in the existing and in future IBM® mainframe servers and onother machines of IBM® (e.g., Power Systems servers and System xServers). They can be executed in machines running Linux on a widevariety of machines using hardware manufactured by IBM®, AMD, andothers. Besides execution on that hardware under a z/Architecture, Linuxcan be used as well as machines which use emulation by Hercules, UMX, orFSI (Fundamental Software, Inc), where generally execution is in anemulation mode. In emulation mode, emulation software is executed by anative processor to emulate the architecture of an emulated processor.

The native processor typically executes emulation software comprisingeither firmware or a native operating system to perform emulation of theemulated processor. The emulation software is responsible for fetchingand executing instructions of the emulated processor architecture. Theemulation software maintains an emulated program counter to keep trackof instruction boundaries. The emulation software may fetch one or moreemulated machine instructions at a time and convert the one or moreemulated machine instructions to a corresponding group of native machineinstructions for execution by the native processor. These convertedinstructions may be cached such that a faster conversion can beaccomplished. Notwithstanding, the emulation software is to maintain thearchitecture rules of the emulated processor architecture so as toassure operating systems and applications written for the emulatedprocessor operate correctly. Furthermore, the emulation software is toprovide resources identified by the emulated processor architectureincluding, but not limited to, control registers, general purposeregisters, floating point registers, dynamic address translationfunction including segment tables and page tables for example, interruptmechanisms, context switch mechanisms, Time of Day (TOD) clocks andarchitected interfaces to I/O subsystems such that an operating systemor an application program designed to run on the emulated processor, canbe run on the native processor having the emulation software.

A specific instruction being emulated is decoded, and a subroutine iscalled to perform the function of the individual instruction. Anemulation software function emulating a function of an emulatedprocessor is implemented, for example, in a “C” subroutine or driver, orsome other method of providing a driver for the specific hardware aswill be within the skill of those in the art after understanding thedescription of the preferred embodiment. Various software and hardwareemulation patents including, but not limited to U.S. Pat. No. 5,551,013,entitled “Multiprocessor for Hardware Emulation”, by Beausoleil et al.;and U.S. Pat. No. 6,009,261, entitled “Preprocessing of Stored TargetRoutines for Emulating Incompatible Instructions on a Target Processor”,by Scalzi et al; and U.S. Pat. No. 5,574,873, entitled “Decoding GuestInstruction to Directly Access Emulation Routines that Emulate the GuestInstructions”, by Davidian et al; and U.S. Pat. No. 6,308,255, entitled“Symmetrical Multiprocessing Bus and Chipset Used for CoprocessorSupport Allowing Non-Native Code to Run in a System”, by Gorishek et al;and U.S. Pat. No. 6,463,582, entitled “Dynamic Optimizing Object CodeTranslator for Architecture Emulation and Dynamic Optimizing Object CodeTranslation Method”, by Lethin et al; and U.S. Pat. No. 5,790,825,entitled “Method for Emulating Guest Instructions on a Host ComputerThrough Dynamic Recompilation of Host Instructions”, by Eric Traut, eachof which is hereby incorporated by reference herein in its entirety; andmany others, illustrate a variety of known ways to achieve emulation ofan instruction format architected for a different machine for a targetmachine available to those skilled in the art.

In FIG. 14, an example of an emulated host computer system 992 isprovided that emulates a host computer system 900′ of a hostarchitecture. In the emulated host computer system 992, the hostprocessor (CPU) 991 is an emulated host processor (or virtual hostprocessor) and comprises an emulation processor 993 having a differentnative instruction set architecture than that of the processor 991 ofthe host computer 900′. The emulated host computer system 992 has memory994 accessible to the emulation processor 993. In the exampleembodiment, the memory 994 is partitioned into a host computer memory996 portion and an emulation routines 997 portion. The host computermemory 996 is available to programs of the emulated host computer 992according to host computer architecture. The emulation processor 993executes native instructions of an architected instruction set of anarchitecture other than that of the emulated processor 991, the nativeinstructions obtained from emulation routines memory 997, and may accessa host instruction for execution from a program in host computer memory996 by employing one or more instruction(s) obtained in a sequence &access/decode routine which may decode the host instruction(s) accessedto determine a native instruction execution routine for emulating thefunction of the host instruction accessed. Other facilities that aredefined for the host computer system 900′ architecture may be emulatedby architected facilities routines, including such facilities as generalpurpose registers, control registers, dynamic address translation andI/O subsystem support and processor cache, for example. The emulationroutines may also take advantage of functions available in the emulationprocessor 993 (such as general registers and dynamic translation ofvirtual addresses) to improve performance of the emulation routines.Special hardware and off-load engines may also be provided to assist theprocessor 993 in emulating the function of the host computer 900′.

In a further embodiment, one or more aspects relate to cloud computing.It is understood in advance that although this disclosure includes adetailed description on cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g. networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based email). Theconsumer does not manage or control the underlying cloud infrastructureincluding network, servers, operating systems, storage, or evenindividual application capabilities, with the possible exception oflimited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting forloadbalancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure comprising anetwork of interconnected nodes.

Referring now to FIG. 15, a schematic of an example of a cloud computingnode is shown. Cloud computing node 1510 is only one example of asuitable cloud computing node and is not intended to suggest anylimitation as to the scope of use or functionality of embodiments of theinvention described herein. Regardless, cloud computing node 1510 iscapable of being implemented and/or performing any of the functionalityset forth hereinabove.

In cloud computing node 1510 there is a computer system/server 1512,which is operational with numerous other general purpose or specialpurpose computing system environments or configurations. Examples ofwell-known computing systems, environments, and/or configurations thatmay be suitable for use with computer system/server 1512 include, butare not limited to, personal computer systems, server computer systems,thin clients, thick clients, handheld or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

Computer system/server 1512 may be described in the general context ofcomputer system executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 1512 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 15, computer system/server 1512 in cloud computing node1510 is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 1512 may include, but are notlimited to, one or more processors or processing units 1516, a systemmemory 1528, and a bus 1518 that couples various system componentsincluding system memory 1528 to processor 1516.

Bus 1518 represents one or more of any of several types of busstructures, including a memory bus or memory controller, a peripheralbus, an accelerated graphics port, and a processor or local bus usingany of a variety of bus architectures. By way of example, and notlimitation, such architectures include Industry Standard Architecture(ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA)bus, Video Electronics Standards Association (VESA) local bus, andPeripheral Component Interconnect (PCI) bus.

Computer system/server 1512 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 1512, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 1528 can include computer system readable media in theform of volatile memory, such as random access memory (RAM) 1530 and/orcache memory 1532. Computer system/server 1512 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 1534 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 1518 by one or more datamedia interfaces. As will be further depicted and described below,memory 1528 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of embodiments of the invention.

Program/utility 1540, having a set (at least one) of program modules1542, may be stored in memory 1528 by way of example, and notlimitation, as well as an operating system, one or more applicationprograms, other program modules, and program data. Each of the operatingsystem, one or more application programs, other program modules, andprogram data or some combination thereof, may include an implementationof a networking environment. Program modules 1542 generally carry outthe functions and/or methodologies of embodiments of the invention asdescribed herein.

Computer system/server 1512 may also communicate with one or moreexternal devices 1514 such as a keyboard, a pointing device, a display1524, etc.; one or more devices that enable a user to interact withcomputer system/server 1512; and/or any devices (e.g., network card,modem, etc.) that enable computer system/server 1512 to communicate withone or more other computing devices. Such communication can occur viaInput/Output (I/O) interfaces 1522. Still yet, computer system/server1512 can communicate with one or more networks such as a local areanetwork (LAN), a general wide area network (WAN), and/or a publicnetwork (e.g., the Internet) via network adapter 1520. As depicted,network adapter 1520 communicates with the other components of computersystem/server 1512 via bus 1518. It should be understood that althoughnot shown, other hardware and/or software components could be used inconjunction with computer system/server 1512. Examples, include, but arenot limited to: microcode, device drivers, redundant processing units,external disk drive arrays, RAID systems, tape drives, and data archivalstorage systems, etc.

Referring now to FIG. 16, illustrative cloud computing environment 1550is depicted. As shown, cloud computing environment 1550 comprises one ormore cloud computing nodes 1510 with which local computing devices usedby cloud consumers, such as, for example, personal digital assistant(PDA) or cellular telephone 1554A, desktop computer 1554B, laptopcomputer 1554C, and/or automobile computer system 1554N may communicate.Nodes 1510 may communicate with one another. They may be grouped (notshown) physically or virtually, in one or more networks, such asPrivate, Community, Public, or Hybrid clouds as described hereinabove,or a combination thereof. This allows cloud computing environment 1550to offer infrastructure, platforms and/or software as services for whicha cloud consumer does not need to maintain resources on a localcomputing device. It is understood that the types of computing devices1554A-N shown in FIG. 16 are intended to be illustrative only and thatcomputing nodes 1510 and cloud computing environment 1550 cancommunicate with any type of computerized device over any type ofnetwork and/or network addressable connection (e.g., using a webbrowser).

Referring now to FIG. 17, a set of functional abstraction layersprovided by cloud computing environment 1550 (FIG. 16) is shown. Itshould be understood in advance that the components, layers, andfunctions shown in FIG. 17 are intended to be illustrative only andembodiments of the invention are not limited thereto. As depicted, thefollowing layers and corresponding functions are provided:

Hardware and software layer 1560 includes hardware and softwarecomponents. Examples of hardware components include mainframes, in oneexample IBM® zSeries® systems; RISC (Reduced Instruction Set Computer)architecture based servers, in one example IBM pSeries® systems; IBMxSeries® systems; IBM BladeCenter® systems; storage devices; networksand networking components. Examples of software components includenetwork application server software, in one example IBM WebSphere®application server software; and database software, in one example IBMDB2® database software. (IBM, zSeries, pSeries, xSeries, BladeCenter,WebSphere, and DB2 are trademarks of International Business MachinesCorporation registered in many jurisdictions worldwide).

Virtualization layer 1562 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers;virtual storage; virtual networks, including virtual private networks;virtual applications and operating systems; and virtual clients.

In one example, management layer 1564 may provide the functionsdescribed below. Resource provisioning provides dynamic procurement ofcomputing resources and other resources that are utilized to performtasks within the cloud computing environment. Metering and Pricingprovide cost tracking as resources are utilized within the cloudcomputing environment, and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal provides access to the cloud computing environment forconsumers and system administrators. Service level management providescloud computing resource allocation and management such that requiredservice levels are met. Service Level Agreement (SLA) planning andfulfillment provide pre-arrangement for, and procurement of, cloudcomputing resources for which a future requirement is anticipated inaccordance with an SLA.

Workloads layer 1566 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation; software development and lifecycle management; virtualclassroom education delivery; data analytics processing; and transactionprocessing.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a”, “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” and/or “comprising”,when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below, if any, areintended to include any structure, material, or act for performing thefunction in combination with other claimed elements as specificallyclaimed. The description of one or more embodiments has been presentedfor purposes of illustration and description, but is not intended to beexhaustive or limited to in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the art. Theembodiment was chosen and described in order to best explain variousaspects and the practical application, and to enable others of ordinaryskill in the art to understand various embodiments with variousmodifications as are suited to the particular use contemplated.

What is claimed is:
 1. A computer-implemented method comprising:activating a virtual adapter hosted on a physical adapter of a hostsystem of a computing environment, the virtual adapter being for use bya guest of the host system in performing data input and output, thevirtual adapter being in an initial state prior to the activating, theactivating being based on a request made to the physical adapter thatthe virtual adapter be activated, wherein the activating activates thevirtual adapter absent involvement of the guest; based on theactivating, constructing configuration information of the activatedvirtual adapter, the configuration information indicative of at least aunique identifier assigned to the activated virtual adapter; providingthe configuration information to a control component; and returning theactivated virtual adapter to the initial state that the virtual adapterwas in prior to the activating, wherein the activating the virtualadapter, the constructing the configuration information, the providingthe configuration information, and the returning the activated virtualadapter to the initial state are performed absent involvement of theguest.
 2. The method of claim 1, further comprising, based ondetermining while the guest is inactive that the configuration is not anappropriate virtual adapter configuration for the guest, reconfiguringthe activated virtual adapter prior to activating the guest.
 3. Themethod of claim 1, wherein the activating activates the virtual adapterabsent the guest being brought online.
 4. The method of claim 1, whereinthe initial state of the virtual adapter comprises a deactivated ornon-configured state, and returning the activated virtual adapter to theinitial state comprises returning the virtual adapter to the deactivatedor non-configured state.
 5. The method of claim 1, wherein theactivating, the constructing, the providing, and the returning areperformed while the guest remains stopped from execution.
 6. The methodof claim 1, wherein the activating, the constructing, the providing, andthe returning are performed with the guest not being loaded into centralelectronic complex memory.
 7. The method of claim 1, wherein the controlcomponent is a component separate from the host system.
 8. The method ofclaim 1, wherein the activating, the constructing, the providing, andthe returning are performed absent communication between the controlcomponent and the guest.
 9. The method of claim 1, wherein theactivating the virtual adapter occurs prior to an initial program loadof the guest.
 10. The method of claim 1, wherein the physical adapter isa hardware host bus adapter of an input-output subsystem of the host,and the physical host bus adapter hosts the virtual adapter.